1. Technical Field
The present invention relates in general to power cables and, in particular, to an improved system, method and apparatus for an electrical power transmission cable having an optical fiber cable for an electrical submersible pump or other downhole tools in subterranean applications.
2. Description of the Related Art
Many types of electrical tools are used in subterranean applications. For example, electrical submersible pumps (ESP) are used to pump fluids from beneath the earth to the surface. Applications for ESPs and other types of downhole tools include geothermal exploration and development, carbon sequestration operations, and oil and gas wells. Such tools are typically powered by transmission cables that extend a long distance from the surface down into the subterranean borehole where the tool is located.
Power may be transmitted to an ESP by banding a specially constructed, three phase electric power cable to the production tubing. The cable is small in diameter, well protected from mechanical abuse and impervious to deterioration of its physical and electrical properties by the hot, aggressive well environments. Cables are available in a wide range of conductor sizes that permit efficient matching to motor requirements. Such cables can be manufactured in either round or flat configurations, using galvanized steel, stainless steel, or monel armor capable of withstanding the hostile environments of an oil well or water well. Solid or stranded electrical conductor construction may be used.
As described herein, the power cables contain several electrical conductors and, in some applications, also contain a smaller fiber optic cable for communications purposes. However, subterranean environments present extreme operational conditions, including certain types of highly corrosive chemicals and gasses that readily destroy the physical integrity and effectiveness of the fiber optic elements. An improved system, method and apparatus for power transmission cables having optical fiber cables for downhole tools in subterranean applications would be desirable.